A nano-pesticide and its preparation method

Abstract

The present invention relates to the technical field of nano-pesticides, and provides a nano-pesticide and a preparation method thereof. By adding a small amount of fluoro-containing nonionic surfactant modified with lipoic acid to the nano-pesticide, not only can the surface tension of the nano-pesticide be reduced to 24-36 mN / m, but also beta-cypermethrin is loaded in the nano-pesticide, overcoming the limitation that existing fluoro-containing surfactants cannot effectively load drugs. Moreover, the encapsulation efficiency of the prepared nano-pesticide reaches 90%-96%, and the drug loading rate reaches 10%-22%, with excellent sustained-release effects. The nano-pesticide and the preparation method provided by the present invention are simple to operate, have a short synthesis route, easy-to-control reaction conditions, are easy to be developed industrially, and have low costs, adding an alternative new variety to the fields of fluoro-containing surfactants and nano-pesticides.

Description

Technical Field

[0001] The present invention relates to the technical field of nano pesticides, and particularly relates to a nano pesticide and a preparation method thereof. Background Art

[0002] Nanoparticles have physicochemical properties such as small particle size, large specific surface area, strong interfacial effect and high penetration ability, which can significantly improve the instability of pesticide active ingredients, promote the deposition of pesticide active molecules on the target and the transfer of dosage, reduce the loss of pesticide active ingredients, and thus improve the utilization rate of pesticides.

[0003] When using surfactants to load pesticides to prepare nano pesticides, traditional hydrocarbon surfactants are generally used at present to reduce the surface tension of aqueous solutions. However, adding a high concentration of hydrocarbon surfactants in nano pesticides can only reduce the surface tension of aqueous solutions to about 35 mN / m, and cannot avoid behaviors such as bouncing and splashing of pesticides on crop leaves, resulting in insufficient absorption by crops and even leading to problems such as pesticide loss and environmental pollution. Fluorinated surfactants can well overcome the above problems.

[0004] Beta-cypermethrin is a pyrethroid insecticide with high biological activity. It is a highly effective isomer of cypermethrin and has contact and stomach toxicity effects. It has a broad insecticidal spectrum, fast knockdown speed, and higher insecticidal activity than cypermethrin. It is suitable for controlling pests on various plants such as cotton, vegetables, fruit trees, tea trees, forests, etc. and hygienic pests. Loading beta-cypermethrin in nano pesticides can significantly enhance the effect of nano pesticides.

[0005] However, due to the hydrophobic and lipophobic properties of fluorine atoms, nano pesticides containing fluorinated surfactants cannot effectively load beta-cypermethrin. Therefore, there is an urgent need to prepare a nano pesticide that loads drugs such as beta-cypermethrin and contains fluorinated surfactants. Summary of the Invention

[0006] The present invention aims to solve at least one of the technical problems existing in the related art. For this reason, the present invention provides a preparation method of a nano pesticide, including the following steps:

[0007] S1: Place in a first solvent, stir to obtain a first mixed solution, add lipoic acid, 4-dimethylaminopyridine and a dehydrating agent to the first mixed solution, and stir for 6-24 h to obtain

[0008] S2: Place It is placed in ultrapure water and stirred to obtain a second mixed solution. Lambda-cyhalothrin is placed in a second solvent and stirred to obtain a third mixed solution. The third mixed solution is dropped into the second mixed solution and stirred for 18 - 24 h, followed by dialysis and freeze-drying to obtain the nano-pesticide loaded with lambda-cyhalothrin;

[0009] Among them, the first solvent is one of acetonitrile, dichloromethane, tetrahydrofuran, dioxane or ethyl acetate;

[0010] The second solvent is one of methanol, acetonitrile, N,N-dimethylacetamide, dimethyl sulfoxide or N,N-dimethylformamide;

[0011] Z is H or F; both m and n are integers, 1 ≤ m ≤ 90, 1 ≤ n ≤ 5.

[0012] According to a preparation method of a nano-pesticide provided by the present invention, the dehydrating agent is one of N,N'-dicyclohexylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride or N,N'-diisopropylcarbodiimide.

[0013] According to a preparation method of a nano-pesticide provided by the present invention, The critical micelle concentration is 0.08 mmol / L - 0.30 mmol / L, and the surface tension is 24 mN / m - 36 mN / m.

[0014] According to a preparation method of a nano-pesticide provided by the present invention, The molar ratio with lipoic acid is 1:1 - 1:2.

[0015] According to a preparation method of a nano-pesticide provided by the present invention, the volume ratio of the third mixed solution to the second mixed solution is 1:10 - 5:10.

[0016] According to a preparation method of a nano-pesticide provided by the present invention, lambda-cyhalothrin and The molar ratio is 1:10 - 5:10.

[0017] The present invention also provides a nano-pesticide prepared by the preparation method of the nano-pesticide as described above, and the particle size of the nano-pesticide is 80 - 200 nm.

[0018] One or more of the above technical solutions in the embodiments of the present invention have at least one of the following technical effects:

[0019] 1. A nano-pesticide provided by the present invention and its preparation method modify lipoic acid on a fluorine-containing non-ionic surfactant, so that the nano-pesticide containing the fluorine-containing non-ionic surfactant is loaded with beta-cypermethrin, overcoming the shackle that the existing fluorine-containing surfactant cannot effectively load drugs, and further improving the application effect of the nano-pesticide.

[0020] 2. The nano-pesticide provided by the present invention and its preparation method are simple to operate, have a short synthesis route, easy-to-control reaction conditions, are easy to industrialize, and have low costs, adding an alternative new variety to the fields of fluorine-containing surfactants and nano-pesticides.

[0021] 3. A nano-pesticide provided by the present invention and its preparation method add a small amount of fluorine-containing non-ionic surfactant to the nano-pesticide, which can reduce the surface tension of the nano-pesticide to 24-36 mN / m, and also make the encapsulation rate of the prepared nano-pesticide reach 90%-96%, and the drug loading rate reach 10%-22%, having an excellent slow-release effect.

[0022] The additional aspects and advantages of the present invention will be partly given in the following description, partly become obvious from the following description, or be understood through the practice of the present invention. Detailed Embodiments

[0023] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below. Apparently, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art without making creative efforts based on the embodiments in the present invention belong to the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but cannot be used to limit the scope of the present invention.

[0024] In addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0025] In the description of this specification, the descriptions referring to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples", etc. mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic descriptions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0026] The present invention provides a preparation method of a nano-pesticide, comprising the following steps:

[0027] S1: Place in a first solvent, stir to obtain a first mixed solution, add lipoic acid, 4-dimethylaminopyridine and a dehydrating agent to the first mixed solution, stir for 6 to 24 h to obtain

[0028] S2: Place in ultrapure water, stir to obtain a second mixed solution, place lambda-cyhalothrin in a second solvent, stir to obtain a third mixed solution, drop the third mixed solution into the second mixed solution, stir for 18 to 24 h, and perform dialysis and freeze-drying to obtain a nano-pesticide loaded with lambda-cyhalothrin;

[0029] Wherein, the first solvent is one of acetonitrile, dichloromethane, tetrahydrofuran, dioxane or ethyl acetate; [[ID=I6]] [[ID=1?]]

[0030] The second solvent is one of methanol, acetonitrile, N,N-dimethylacetamide, dimethyl sulfoxide or N,N-dimethylformamide;

[0031] Z is H or F; m and n are both integers, 1 ≤ m ≤ 90, 1 ≤ n ≤ 5.

[0032] Wherein, the operation steps of dialysis are: put the mixed solution obtained after stirring into a dialysis bag, perform dialysis for 12 to 24 h, then perform freeze-drying, and finally obtain a nano-pesticide loaded with lambda-cyhalothrin.

[0033] Wherein, in order to overcome the hydrophobic and lipophobic properties of fluorine atoms, the inventors conducted screening experiments among various substances and finally selected lipoic acid. The main reason is that the structure of lipoic acid contains more carbon-hydrogen chains, which can effectively load lambda-cyhalothrin. In addition, the hydroxyl group in

[0034] and the carboxyl group of lipoic acid can undergo an esterification reaction, the preparation steps are simple, and lipoic acid has a low cost and is also an environmentally friendly molecule, further improving the degradability of the nano-pesticide prepared in this application.

[0035] According to the preparation method of a nano-pesticide provided by the present invention, the dehydrating agent is one of N,N'-dicyclohexylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride or N,N'-diisopropylcarbodiimide. The critical micelle concentration of

[0036] A preparation method of a nano-pesticide provided by the present invention The molar ratio with lipoic acid is 1:1 to 1:2.

[0037] According to the preparation method of a nano-pesticide provided by the present invention, the volume ratio of the third mixed solution to the second mixed solution is 1:10 to 5:10.

[0038] According to the preparation method of a nano-pesticide provided by the present invention, lambda-cyhalothrin and The molar ratio is 1:10 to 5:10.

[0039] The present invention also provides a nano-pesticide prepared by the preparation method of the nano-pesticide as described above, and the particle size of the nano-pesticide is 80 to 200 nm.

[0040] The following describes a nano-pesticide and its preparation method provided by the present invention through Examples 1-16:

[0041] It should be noted that:

[0042] The measurement methods of the surface tension of are all: prepare a series of solutions with different concentrations of The surface tension is measured by the du Noüy ring method using a JK99M fully automatic static surface tension meter (outer diameter 20.30 mm, platinum wire 0.30 mm, circumference 61.89 mm, density 0.998 g / cm 3 , temperature 25 ± 1 °C). The instrument is calibrated with pure water before and after the test.

[0043] The retention time and peak area of lambda-cyhalothrin in the nano-pesticide are determined by high performance liquid chromatography. The test conditions for the lambda-cyhalothrin standard solution are OBS2-C 18 Reverse phase chromatographic column, column temperature 25 °C, mobile phase is a mixed phase of methanol: water = 80:20, flow rate is 1 mL / min, injection volume is 20 μL, detection wavelength is 220 nm. The peak area of lambda-cyhalothrin measured is linearly fitted with Origin to draw a standard curve.

[0044] After testing, the retention time of lambda-cyhalothrin is 25.9 min, and its standard curve is y = 0.01624x + 0.51948, R 2 = 0.99903. This standard curve has a good linear relationship, and the mass of lambda-cyhalothrin encapsulated in the nano-pesticide (the total mass of lambda-cyhalothrin in the nano-pesticide) is calculated through this linear equation. Among them, R 2 refers to the correlation coefficient.

[0045] Control the third mixed solution and the second mixed solution to be mixed at a certain volume ratio (total volume 20 mL), change the feeding ratio and the type of organic solvent, and determine the encapsulation efficiency and drug loading rate of the nano-pesticide according to the following formula.

[0046]

[0047]

[0048] Take 95 mL of the release medium of 70% ethanol (ethanol: water = 70:30) in a 250 mL beaker. Weigh 10.0 mg of lambda-cyhalothrin in a 10 mL centrifuge tube. After dissolving it with 5 mL of the release medium, place it in a dialysis bag with a molecular retention volume of 500 that has been treated. Seal both ends and place it in the beaker. Stir and dialyze at a rotation speed of 300 r / min. Take 5 mL of the dialysis solution from the beaker at regular intervals. When taking out 5 mL, add an equal volume of the release medium to the beaker to keep the volume of the release medium in the beaker unchanged. Measure its content using high performance liquid chromatography, and calculate its cumulative release rate according to the cumulative release rate formula:

[0049]

[0050] Among them, Q: cumulative release rate; W: total mass of lambda-cyhalothrin in the nano-pesticide; V0: volume of the release medium; C T : concentration of lambda-cyhalothrin in the release medium corresponding to the sampling time point; V: volume of each sampling; C i : concentration of lambda-cyhalothrin at the i-th sampling.

[0051] The structure is The preparation method of the intermediate is referred to Chinese Patent CN114276537 A. It is prepared by reacting polyethylene glycol with epibromohydrin and then reacting with fluorinated alcohol. Both polyethylene glycol and fluorinated alcohol are environmentally friendly organic substances and are easy to degrade.

[0052] Example 1

[0053] Dissolve the surfactant with the structure of in dichloromethane, add lipoic acid in a molar ratio of 1:1.5, then add 4-dimethylaminopyridine and N,N'-diisopropylcarbodiimide, stir, and react at room temperature for 6 h to obtain an environmentally friendly fluorinated nonionic surfactant Label it as C1.

[0054] After testing, the critical micelle concentration of the fluorinated nonionic surfactant C1 prepared in this example is 0.30 mmol / L, and the corresponding surface tension is 36 mN / m.

[0055] Example 2

[0056] Dissolve the surfactant with the structure of in acetonitrile, add lipoic acid in a molar ratio of 1:1, then add 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide, stir, and react at room temperature for 8 h to obtain an environmentally friendly fluorinated nonionic surfactant Label it as C2.

[0057] After testing, the critical micelle concentration of the fluorinated nonionic surfactant C2 prepared in this example is 0.21 mmol / L, and the corresponding surface tension is 32 mN / m.

[0058] Example 3

[0059] Dissolve the surfactant with the structure of in tetrahydrofuran, add lipoic acid in a molar ratio of 1:2, then add 4-dimethylaminopyridine and N,N'-diisopropylcarbodiimide, stir, and react at room temperature for 13 h to obtain an environmentally friendly fluorinated nonionic surfactant Label it as C3.

[0060] After testing, the critical micelle concentration of the fluorinated nonionic surfactant C3 prepared in this example is 0.16 mmol / L, and the corresponding surface tension is 27 mN / m.

[0061] Example 4

[0062] Dissolve the surfactant with the structure of in ethyl acetate, add lipoic acid in a molar ratio of 1:2, then add 4-dimethylaminopyridine and N,N'-dicyclohexylcarbodiimide, stir, and react at room temperature for 24 h to obtain an environmentally friendly fluorinated nonionic surfactant Label it as C4.

[0063] After testing, the critical micelle concentration of the fluorinated nonionic surfactant C4 prepared in this example is 0.08 mmol / L, and the corresponding surface tension is 24 mN / m.

[0064] Example 5

[0065] Dissolve the surfactant with the structure of in dioxane, add lipoic acid in a molar ratio of 1:1.8, then add 4-dimethylaminopyridine and 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride, stir, and react at room temperature for 18 h to obtain an environmentally friendly fluorinated nonionic surfactant Label it as C5.

[0066] After testing, the critical micelle concentration of the fluorinated nonionic surfactant C5 prepared in this example is 0.18 mmol / L, and the corresponding surface tension is 28 mN / m.

[0067] Example 6

[0068] Dissolve the fluorinated nonionic surfactant C1 prepared in Example 1 in ultrapure water, stir, and then slowly add the lambda-cyhalothrin dissolved in acetonitrile to the aqueous solution of C1. The volume ratio of the third mixed solution to the second mixed solution is 1:10, and the molar ratio of lambda-cyhalothrin to C1 is 5:10. After stirring for 18 h, put it into a dialysis bag, dialyze for 16 h, and then freeze-dry to obtain the nano-pesticide loaded with lambda-cyhalothrin, which is labeled as N1.

[0069] After testing, the encapsulation efficiency of the nano-pesticide N1 loaded with the fluorinated nonionic surfactant and lambda-cyhalothrin prepared in this example is 90.2%, and the drug loading rate is 12.3%.

[0070] Example 7

[0071] Dissolve the fluorinated nonionic surfactant C2 in Example 2 in ultrapure water, stir, and then slowly add the lambda-cyhalothrin dissolved in N,N-dimethylformamide to the aqueous solution of C2. The volume ratio of the third mixed solution to the second mixed solution is 5:10, and the molar ratio of lambda-cyhalothrin to C2 is 1:10. After stirring for 21 h, put it into a dialysis bag, dialyze for 12 h, and then freeze-dry to obtain the nano-pesticide loaded with lambda-cyhalothrin, which is labeled as N2.

[0072] After testing, the encapsulation efficiency of the nano-pesticide N2 loaded with the fluorinated nonionic surfactant and lambda-cyhalothrin prepared in this example is 94.2%, and the drug loading rate is 13.1%.

[0073] Example 8

[0074] Dissolve the fluorinated nonionic surfactant C3 in Example 3 in ultrapure water, stir, and then slowly add the lambda-cyhalothrin dissolved in dimethyl sulfoxide to the aqueous solution of C3. The volume ratio of the third mixed solution to the second mixed solution is 2:10, and the molar ratio of lambda-cyhalothrin to C3 is 4:10. After stirring for 24 h, put it into a dialysis bag, dialyze for 24 h, and then freeze-dry to obtain the nano-pesticide loaded with lambda-cyhalothrin, which is labeled as N3.

[0075] After testing, the encapsulation efficiency of the nano-pesticide N3 loaded with the fluorinated nonionic surfactant and lambda-cyhalothrin prepared in this example is 92.1%, and the drug loading rate is 18.3%.

[0076] Example 9

[0077] Dissolve the fluorinated nonionic surfactant C4 in Example 4 in ultrapure water and stir. Then, slowly add the lambda-cyhalothrin dissolved in N,N-dimethylacetamide dropwise to the aqueous solution of C4. The volume ratio of the third mixed solution to the second mixed solution is 3:10, and the molar ratio of lambda-cyhalothrin to C4 is 2:10. After stirring for 22 h, put it into a dialysis bag with a molecular cut-off of 500 that has been treated. After dialysis for 20 h, freeze-dry to obtain the nano-pesticide loaded with lambda-cyhalothrin, which is labeled as N4.

[0078] After testing, the encapsulation efficiency of the nano-pesticide N4 loaded with lambda-cyhalothrin prepared in this example is 93.6%, and the drug loading rate is 17.3%.

[0079] Example 10

[0080] Dissolve the fluorinated nonionic surfactant C5 in Example 5 in ultrapure water and stir. Then, slowly add the lambda-cyhalothrin dissolved in methanol dropwise to the aqueous solution of C5. The volume ratio of the third mixed solution to the second mixed solution is 2:10, and the molar ratio of lambda-cyhalothrin to C5 is 3:10. After stirring for 18 h, put it into a dialysis bag. After dialysis for 22 h, freeze-dry to obtain the nano-pesticide loaded with lambda-cyhalothrin, which is labeled as N5.

[0081] After testing, the encapsulation efficiency of the nano-pesticide N5 loaded with lambda-cyhalothrin prepared in this example is 91.9%, and the drug loading rate is 19.2%.

[0082] Table 1 Comparison table of the properties of fluorinated nonionic surfactants and nano-pesticides

[0083]

[0084] As can be seen from Table 1, the surface tension of the fluorinated nonionic surfactant provided by the present invention is 28 - 36 mN / m, and the surface tension of the nano-pesticide added with the fluorinated nonionic surfactant can also reach 28 - 36 mN / m. The surface tension affects the retention time of the nano-pesticide on the plant leaf surface. The smaller the surface tension, the longer the drug retention time, and the less likely it is to bounce, splash, etc. By controlling the reaction conditions, the encapsulation efficiency of the nano-pesticide can reach 90% - 96%. The higher the encapsulation efficiency, the better the stability of the nano-pesticide and the longer the storage period. The drug loading rate of the nano-pesticide can also reach 10% - 22%. The higher the drug loading rate, the better the efficacy of the nano-pesticide. Therefore, the nano-pesticide prepared by the present invention has excellent slow-release effects.

[0085] Example 11

[0086] The particle sizes of the nano-pesticides containing fluorinated nonionic surfactants loaded with beta-cyfluthrin prepared in Examples 6-10 are shown in Table 2:

[0087] Table 2 Particle Sizes of Nano-Pesticides

[0088]

[0089]

[0090] As can be seen from Table 2, the particle sizes of the nano-pesticides N1-N5 prepared in the present invention range from 80 to 200 nm, indicating that the synthesis route of the method for preparing the nano-pesticides provided by the present invention is stable and can be developed and prepared industrially.

[0091] Example 12

[0092] The cumulative release rate of the nano-pesticide prepared by loading beta-cyfluthrin with the fluorinated nonionic surfactant in Example 6 was measured, and the results are shown in Table 3.

[0093] Table 3 Cumulative Release Rates of Nano-Pesticides

[0094]

[0095]

[0096] According to Table 3, the cumulative release rate of the nano-pesticide N1 prepared in Example 6 was tested, and the cumulative release rate of N1 could reach 75%, indicating that the nano-pesticide N1 prepared in the present invention has a good slow-release effect.

[0097] Example 13

[0098] The cumulative release rate of the nano-pesticide prepared by loading beta-cyfluthrin with the fluorinated nonionic surfactant in Example 7 was measured, and the results are shown in Table 4.

[0099] Table 4 Cumulative Release Rates of Nano-Pesticides

[0100]

[0101]

[0102] According to Table 4, the cumulative release rate of the nano-pesticide N2 prepared in Example 7 was tested, and the cumulative release rate of N1 could reach 57.2%, indicating that the nano-pesticide N2 prepared in the present invention has a good slow-release effect.

[0103] Example 14

[0104] The cumulative release rate of the nano-pesticide prepared by loading beta-cyfluthrin with the fluorinated nonionic surfactant in Example 8 was measured, and the results are shown in Table 5.

[0105] Table 5 Cumulative release rate of nano - pesticides

[0106] Time (h) Cumulative release rate 0 0 1 12.9 3 24.3 5 30.5 7 34.1 9 36.3 12 40.2 24 48.7 36 54.2 48 59.6 60 66.4 72 70.1 108 74.6

[0107] As shown in Table 5, the cumulative release rate of the nano - pesticide N3 prepared in Example 8 was tested, and the cumulative release rate of N3 could reach 74.6%, indicating that the nano - pesticide N3 prepared by the present invention has a good sustained - release effect.

[0108] Example 15

[0109] The cumulative release rate of the nano - pesticide prepared by the fluorine - containing non - ionic - loaded lambda - cyhalothrin in Example 9 was measured, and the results are shown in Table 6.

[0110] Table 6 Cumulative release rate of nano - pesticides

[0111] Time (h) Cumulative release rate 0 0 1 9.7 3 21.6 5 29.2 7 37.9 9 42.7 12 43.6 24 45.3 36 45.6 48 46.7 60 48.6 72 49.8 108 50.0

[0112] As shown in Table 6, the cumulative release rate of the nano - pesticide N4 prepared in Example 9 was tested, and the cumulative release rate of N4 could reach 50%, indicating that the nano - pesticide N4 prepared by the present invention has a good sustained - release effect.

[0113] Example 16

[0114] The cumulative release rate of the nano - pesticide prepared by the fluorine - containing non - ionic - loaded lambda - cyhalothrin in Example 10 was measured, and the results are shown in Table 7.

[0115] Table 7 Cumulative release rate of nano - pesticides

[0116] Time (h) Cumulative release rate 0 0 1 12.7 3 17.5 5 23.8 7 32.4 9 39.7 12 42.2 24 49.7 36 55.3 48 61.2 60 66.9 72 67.6 108 68.4

[0117] As shown in Table 7, the cumulative release rate of the nano - pesticide N5 prepared in Example 10 was tested, and the cumulative release rate of N5 could reach 68.4%, indicating that the nano - pesticide N5 prepared by the present invention has a good sustained - release effect.

[0118] Finally, it should be noted that the above - mentioned embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A preparation method of a nano-pesticide, characterized in that, It includes the following steps: S1: Place in a first solvent, stir to obtain a first mixed solution, add lipoic acid, 4-dimethylaminopyridine and a dehydrating agent to the first mixed solution, and stir for 6 to 24 h to obtain ; Among them, The molar ratio with lipoic acid is 1:1 to 1:2; S2: Place in ultrapure water and stir to obtain a second mixed solution. Place lambda-cyhalothrin in a second solvent and stir to obtain a third mixed solution. Drop the third mixed solution into the second mixed solution and stir for 18 - 24 h, then perform dialysis freeze-drying to obtain a nano-pesticide loaded with lambda-cyhalothrin. Among them, the first solvent is one of acetonitrile, dichloromethane, tetrahydrofuran, dioxane or ethyl acetate; The second solvent is one of methanol, acetonitrile, N,N-dimethylacetamide, dimethyl sulfoxide or N,N-dimethylformamide; Z is H or F; Both m and n are integers, 1 ≤ m ≤ 90, 1 ≤ n ≤ 5; The particle size of the nano-pesticide is 80 - 200 nm, the encapsulation efficiency is 90% - 96%, and the drug loading rate is 10% - 22%.

2. The preparation method of the nano-pesticide according to claim 1, characterized in that, The dehydrating agent is one of N,N'-dicyclohexylcarbodiimide, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride or N,N'-diisopropylcarbodiimide; 3. The preparation method of the nano-pesticide according to claim 1, characterized in that, The critical micelle concentration is 0.08 mmol / L to 0.30 mmol / L, and the surface tension is 24 mN / m to 36 mN / m.

4. The preparation method of the nano-pesticide according to claim 1, wherein, The volume ratio of the third mixed solution to the second mixed solution is 1:10 - 5:

10.

5. The preparation method of the nano-pesticide according to claim 1, characterized in that, Lambda-cyhalothrin and The molar ratio is 1:10 to 5:10.

Images